Powerfc New Injector Settings

[CameronBNR32]

Ok, lets see if I can explain this cleary I have just recently upgraded my fuel system again, and since putting in the powerfc injector settings the car wont start. ( R32 GTR RB26 )

The car was running nismo 600cc injectors and now I am running the Sard 800cc twin sprays.

Using the properties for the injectors:

Stock Injectors are 444cc/0.77msec latency

Old Injectors are: 600cc/0.81msec latency

New Injectors are: 800cc/1.10msec latency

The oringinal settings for the 600cc's on the powerfc were:

Injector- 74% (444/600) Latency- +0.04 (0.81-0.77)

that obviosly ran fine....

soooo, first try I put in the settings for the new injectors

Injector- 55% (444/800) and Lantency- +0.33 (1.10-0.77)

...........doesn't start

so I thought.... well its tuned for the 600s, so maybe I'll do the injectors corrections for them?

Injector- 75% (600/800) and Latency- +0.29 (1.10-0.81)

...........doesn't start

so now I've checked fuel pressure in the rail and going by the manual of 42psi, its all there, holds pressure on purge and cranking...

am I doing the injector corrections right??? The battery is now being recharged from been drained flat from cranking and purging pumps, so I'm trying to find if I'm missing something.

Edited February 24, 2007 by CameronBNR32

[paulr33]

anything odd in SENSOR SW CHECK ?

engine check light come on ?

does the engine start and then stall or wont start?

[CameronBNR32]

anything odd in SENSOR SW CHECK ?

engine check light come on ?

does the engine start and then stall or wont start?

I did check all the sensors and they were all registering

The engine will sometimes 'puff' but wont get anywhere near idling/starting so all the dash lights are still on.

At the moment I'm pulling out the plugs to see if they are wet and see if any fuel is actually getting in there.

[paulr33]

logic says to me it should be;

Old Injectors are: 444cc/0.77msec latency

New Injectors are: 800cc/1.10msec latency

and then do it based on that, forget that you have 600cs previously

[CameronBNR32]

I pulled the plugs out, the injectors were damp, but not as wet as I would expect them to be..

Does anyone know the exact Latency for the Sard 800cc Twin Sprays? I only found one resource that said 1.10msec... couldnt find much info at all.

[CameronBNR32]

OK! its all sweet now, runs and idles.

I pulled the plugs out and cleaned them, so maybe they were a little fowled from fuel...

thanks all!

*sigh of releif*

[paulr33]

can u pm me which injector settings (correct, latency) and i will add to pfc faq

[CameronBNR32]

can u pm me which injector settings (correct, latency) and i will add to pfc faq

done and done

[BOOSTD]

The oringinal settings for the 600cc's on the powerfc were:

Injector- 74% (444/600) Latency- +0.4 (0.81-0.77)

don't u mean .81-.77=.04 .............maybe double check your input for the 800's

[CameronBNR32]

The oringinal settings for the 600cc's on the powerfc were:

Injector- 74% (444/600) Latency- +0.4 (0.81-0.77)

don't u mean .81-.77=.04 .............maybe double check your input for the 800's

It was 0.04 in the powerfc, just a typo by me

thanks

[Birnie]

Outta interest, do you guys change your values and the tune is still perfect with the bigger injectors...so WOT whenever or do you take it easy and just use it as a bandaid type fix....ie enough to get you to a tuner to get it sorted properly?

[The Alchemist]

When you change injector sizing, for what ever reason, you will need to have the map touched up to suit as the change in size can affect the fuel delivery slightly at certain loads and RPM. The touch up is a quick affair that would only take an hour at the most. BUT, if you're not fussy, you can get away with no changes whatsoever. Its up to you.

In other areas such as startup fuel and accel pump fuel, these settings are in injector ms times and ARE NOT CHANGED WHEN YOU RESCALE THE INJECTORS !!!!.

That lovely puff of black smoke, even on light throttle changes is the accel pump fuel and with larger injectors like 700CC can be a cloud of black smoke at the lights. The PFC settings for accel pump fuel are around 4.5 to 5ms standard and with larger injectors I have reduced these times to about 1.2 to 1.5ms with no black smoke and perfect throttle response (actually got better the more I reduced it) . Fuel usage also reduced dramatically.

Hope this helps,

Mike

[CameronBNR32]

I only change the injectors sizing and drive on that tune so I can drive it to get properly dyno tuned.

[Topaz]

The oringinal settings for the 600cc's on the powerfc were:

Injector- 74% (444/600) Latency- +0.4 (0.81-0.77)

don't u mean .81-.77=.04 .............maybe double check your input for the 800's

I set my PFC to these settings after installing 600cc injectors and had no luck getting my car to idle at all. Had to take it in for a retune in the end

[BOOSTD]

Quote

"SARD 800cc twin hole

Injector- 55% (444/800) and Lantency- +0.33 (1.10-0.77)"

Are these the correct settings, I have just installed some.

going by the PFC FAQ .77-1.10 = minus .33 ?????

Edited April 10, 2007 by BOOSTD

[BOOSTD]

Anyone.....Pls

[Cubes]

Cameron,

A mate recently dropped a set of Sard 800cc twinsprays in to his setup.

He runs the rb20det pfc on his rb30det and using the technically correct values the thing just would not run.

I played with the values (what they are; I can't remember) until it ran and got the o2 sensor swinging.

The only thing I could think of is the twinsprays some how throw everything out, we didn't check fuel pressure all though once on the dyno all appeared to be good. Perfect cold/warm starts, no drivability issues, excellent fuel economy and expected duty cycle for the power being made.

To this day it still won't run with the technically correct injector size and lag trim.

He also runs a Z32 afm.

I've seen the rb20t pfc do funky things previously when running a non-std afm.

Your problem isn't related but for others in the future.

[BOOSTD]

I've just done a basic road tune. injector lag is set to +32, and correction 55%. AFM correction however has been changed so at idle is 50% which quickly changes to 115% after 1.5v on the AFM's.....very strange. I also changed the correction values for voltage standard injectors are .772 @ 14v so I calculated the % change at each voltage and input the values for 1.10msec injectors. I've also halved the accel enrichment which seems to run well. Car runs 1.8bar nicely with very stable AFR and very low knock.....just have to get some more spark...I think my plugs are already at .6mm ...damn it, lol

[BOOSTD]

Quote

"SARD 800cc twin hole

Injector- 55% (444/800) and Lantency- +0.33 (1.10-0.77)"

Are these the correct settings, I have just installed some.

going by the PFC FAQ .77-1.10 = minus .33 ?????

PFC FAQ is wrong,

its definately

New lag time - old lag time. so +.33 for my 800cc 1.10msec

[CameronBNR32]

Sorry BOOSTD, I havn't been checking back with this thread as I thought it had died.

The injector lag and size value caculation I worked off was in my powerfc user manual.

The settings I have in my car at the moment are:

Injector- 55% (444/800)

Lantency- +0.33 (1.10-0.77

it starts and runs, but runs rich (I'm not sure the reason to running rich is the setting on the new fuel regulator).

Cubes- RB20 powerfc on a RB30? wouldn't that be the problem

I've got to get my tuned asap, hasnt moved since the thread has been made! I need to stop modifing the dam thing!

Edited April 28, 2007 by CameronBNR32